Apparatus for punching interlocking tabs in steel strips



D 12, F. J. MOLTCHAN APPARATUS FOR PUNCHING INTERLOCKING TABS IN STEELSTRIPS Filed Aug. 1, 1966 cJ. M01522? Floyd 7 ATTORNEY.

United States Patent l 3,357,078 APPARATUS FOR PUNCHlNG INTERLOCKINGTABS IN STEEL STRIPS Floyd J. Moltchau, 4450 Lake Park Road, Youngstown,Ohio 44512 Filed Aug. 1, 1966, Ser. No. 569,144 4 Claims. (Cl. 29--21.1)

This invention relates to strip material handling apparatus and moreparticularly to apparatus for joining the leading end of one section ofsteel strip to the trailing end of an adjacent section so that thejoined sections can continue through a processing or production line ina continuous manner.

The principal object of the invention is the provision of apparatus forforming interlocking tabs in steel strips and shaping the interlockingtabs so as to decrease the relative size thereof sufiiciently to permitthe shaped interlocking tabs to move freely out of the apparatus.

A further object of the invention is the provision of a simpleinexpensive and quick acting apparatus for punching interlocking tabs insteel strips arranged to deflect the steel strips to be joined by theinterlocking tabs downwardly into one part of the apparatus where theinterlocking tabs are formed and interlocked and subsequently, elevatingthe steel strips and interlocked tabs out of that part of the apparatusso as to permit the joined steel strips to move freely relative to saidapparatus.

Several methods of joining adjacent end portions of steel strips to oneanother have been heretofore known and used in the metal working arts.Primarily, these have comprised devices for welding the strips to oneanother and such devices work effectively but are relatively expensiveand require a considerable time pause in the portions of the strips tobe joined which necessitate large loop sections in the strip toaccommodate the same particularly in a continous mill or production lineset up.

Other proposals heretofore made have included devices for stitching orforming interlocking tabs. These have generally failed due to theinherent problem of freeing the interlocking tabs or stitched portion ofthe strip material from the forming or stitching apparatus. The presentinvention provides a unique apparatus having a relatively wide pass lineor area therethrough through which the strips to be joined may freelypass. At such time as the superimposed adjacent ends of two sections ofthe steel strip are present in the apparatus the appara tus moves towardthe strips, engages the same, punches the interlocking tabs and deflectsthem downwardly while altering the transverse shape and size of the sameso as to make possible the immediate freeing of the deflectedinterlocked tabs from the apparatus which performed the actualinterlocking operation.

With the foregoing and other objects in view which will appear as thedescription proceeds, the invention resides in the combinationarrangement of parts and in the details of construction hereinafterdescribed and claimed, it being the intention to cover all changes andmodifications of the example of the invention herein chosen for purposesof the disclosure, which do not constitute departures from the spiritand scope of the invention.

The invention is illustrated in the accompanying drawing, wherein:

FIGURE 1 is a side elevation of the apparatus for punching interlockingtabs in steel strips showing the same in fully engaged tab formingposition.

FIGURE 2 is a side elevation of the interlocked steel strips.

FIGURE 3 is a top plan view of the interlocked steel stri s.

P IGURE 4 is a side elevation of the interlocked steel 3,357,078Patented Dec. 12, 1967 strips showing the interlocking tabs undertension and their relative movement responsive thereto.

FIGURE 5 is an expanded cross section on line 5-5 of FIGURE 2.

FIGURE 6 is an expanded cross section similar to FIGURE 5 showing amodified transverse configuration of the interlocking tabs.

By referring to the drawings and FIGURE 1 in particular, it will be seenthat a die 10 is illustrated positioned below a horizontal pass line andincludes a vertical opening 11 therein in which a punch 12 is adapted tobe engaged when the same is moved downwardly by a punch retainer 13which in turn is carried by a movable top die shoe as will be understoodby those skilled in the art. The die 10 is mounted on a bottom die shoe14 which is partially illustrated and which slidably positions a springretainer 15 in which a suitable spring device 16 is located. The upperend of the spring retainer 15 supports a vertically movable ejector 17which is positioned alongside a form steel 18 which is also located inthe die 10 and in the vertical opening 11 thereof. A stripper 19 whichis apertured as at 20 is positioned in spaced relation above the die 10and below the punch retainer 13 and arranged so that the punch 12 isreciprocal through the opening 20.

In FIGURE 1 of the drawings broken lines illustrate a pair ofsuperimposed steel strips. The leading end 21 of one of the strips isshown positioned on the trailing end 22 of the other of steel strips.When the apparatus for punching interlocking tabs in these steel stripsis actuated and the interlocking tabs formed thereby the apparatusincluding the punch 12 and the form steel 18 and the ejector 17 are inthe position illustrated in FIG- URE 1 and a pair of superimposed tabs23 and 24 are formed respectively in the strips 21 and 22 and deflecteddownwardly in the forming operation. The punch 12 has an angular concavemetal shaping surface, the uppermost portion of the concave surfacebeing indicated by the numeral 25 and the form steel 18 has an angularlydisposed convex metal shaping surface 26 generally matching theconcaveconfiguration 25 in the punch 12. Thus, when the punch 12 engagesthe superimposed steel strips 21 and 22 it first punches the tabs 23 and24 therefrom in a punching action and then moves on downwardly to shapethe tabs 23 and 24 by means of the configurations 25 and 26. The concaveconfiguration 25 and the convex configuration 26 in the punch 12 andform steel 18, respectively, are such that the metal of the tabs 23 and24 is humped upwardly in their center longitudinal section as best seenin the cross section in FIGURE 5 of the drawings or in the sideelevation of FIGURE 2 of the drawing whereby the effective overall widthof each of the tabs 23 and 24 is reduced relative to the openings in thestrips 21 and 32 from which the tabs were punched.

Those skilled in the art will observe that tabs 23 and- 24 are notcompletely separated from the strips 21 and 22 but remain joined theretoalong their foremost edges. The tabs are themselves deflected to anangular position below the superimposed strips 21 and 22 and thelongitudinal centrally positioned hump shape formed in the tabs 23 and24 extends from their point of junction with the strips 21 and 22downwardly through substantially their entire length. -By creating thelongitudinal hump in the tabs 23 and 24 their effective width is reducedand they are, therefore, relatively free of the surrounding die 10 andin a position and shape so that the ejector 17 moved by the springdevice 16 lifts them upwardly and out of the opening 11 in the die 10 assoon as the punch 12 is retracted upwardly. The stripper 19 prevents thestrip 21 from following the punch 12 upwardly when it retracts as it ispositioned in fixed relation to the pass line by suitable supportingarms 27.

By referring now to FIGURES 2 and 3 of the drawings, a side elevationand a top plan view of the strips 21 and 22 may be seen, and it will beobserved that the tabs 23 and 24 are shown after the same have moved outof the apparatus for punching the interlocking tabs therein and thatthey are still in the as formed relation.

By refrring now to FIGURE 4 of the drawings, it will be seen that thetension on the trailing end of the strip 22 moves the same relative tothe strip 21 and thus shifts the position of the interlocking tabs 23and 24 and that in such shifted position the tab 23 underlies a portionof the strip 22 and thereby holds the leading end of the strip 21 infixed relation thereto thereby achieving the principal object of theinvention.

It will occur to those skilled in the art that while the embodiment ofthe invention illustrated herein shows only one pair of interlockingtabs in rather narrow steel strip, the usual application of theapparatus to a strip line will require a plurality of the punches 12 anddies and form steels 18 as shown herein, arranged in a line transverselyof the pass line and the steel strip moving therealong. In such anarrangement the plurality of punches 12 and dies 10 move toward oneanother and the steel strip simultaneously and form a transverse line ofpunched interlocking tabs thereacross.

By referring now to FIGURES 4 and 5 of the drawings, it will be seenthat when the tabs 23 and 24 are punched and formed as hereinbeforedescribed, the central longitudinal portion of each of the tabs forms araised angularly disposed ridges 28 and 29 respectively and that themovement of the metal of the tab into the ridge 28 or 29 reduces theireffective width as clearly shown in the top plan view of FIGURE 3 andwith respect to the punched opening 30 from which the tab 23 was formed.

In FIGURE 5 of the drawings vertical lines spaced on either side of thesuperimposed tabs 23 and 24 indicate the width of the tabs 23 and 24 atthe time they are punched from the strips 21 and 22 while the actualcross sectional views thereof show the same in their reduced widthresulting from their appropriate shaping as disclosed herein.

In FIGURE 6 of the drawings a modification of a pair of interlockingtabs 31 and 32 may be seen and it will be observe-d that these areshaped in a modified transverse configuration which also effectivelyreduces the width of the tabs. It will thus be seen that an apparatusfor punching interlocking tabs in steel strips so that the tabs may befreely moved out of the punching die and apparatus has been disclosedand which apparatus accordingly meets the several objects of theinvention. It will occur to those skilled in the art that when the punch12 and die 10 move away from one another as hereinbefore described,after completing the formation of the interlocking tabs 23 and 24 andshaping the same, the vertical spacing between these respective partsincreases substantially and sufficiently to permit the tabs 23 and 24 tobe moved upwardly thereinto by the ejector 17 and to permit the strips21 and 22 to move freely between the metal working parts of theapparatus.

Having thus described my invention, what I claim is:

1. Apparatus for punching interlocking tabs in superimposed steel stripsconsisting of a die, said die having a cutting edge in the shape of saidtabs, and a punch registrable with said die, said punch having a cuttingedge in the shape of said tabs, a portion of said die having a formingsurface, a portion of said punch having a matching forming surface, saidforming surfaces arranged to move the metal of said tabs formed therebyto superimposed shapes of a size smaller than the areas from which theywere formed.

2. The apparatus set forth in claim 1 and wherein said punch and die areformed to shape said tabs so that they are each joined to said steelstrips at one of their ends and deflected downwardly relatively thereto.

3. The apparatus set forth in claim 1 and wherein said punch and die areformed to shape said tabs to include axial extending ribs on their uppersides.

4. The apparatus set forth in claim 1 and wherein said forming surfacein said punch consists of an angular positioned concave channel and theforming surface of said die consists of an angular positioned convexridge.

References Cited UNITED STATES PATENTS 184,397 11/1876 Macumber.2,811,880 11/1957 Williams.

RICHARD H. EANES, JR, Primary Examiner.

1. APPARATUS FOR PUNCHING INTERLOCKING TABS IN SUPERIMPOSED STEEL STRIPSCONSISTING OF A DIE, SAID DIE HAVING A CUTTING EDGE IN THE SHAPE OF SAIDTABS, AND A PUNCH REGISTRABLE WITH SAID DIE, SAID PUNCH HAVING A CUTTINGEDGE IN THE SHAPE OF SAID TABS, A PORTION OF SAID DIE HAVING A FORMINGSURFACE, A PORTION OF SAID PUNCH HAVING A MATCHING FORMING SURFACE, SAIDFORMING SURFACES ARRANGED TO MOVE THE METAL OF SAID TABS FORMED THEREBYTO SUPERIMPOSED SHAPES OF A SIZE SMALLER THAN THE AREAS FROM WHICH THEYWERE FORMED.